Multiple centrifugal casting



June 12 1945 c. E. soRl-:NsEN Erm.

MULTIPLE CENTRIFUGAL CASTING Filed May 23, 1942 www ATTORNEYS.

Patented Jun-1z,'1`945 Charles E. Sorensen, Detroit, and Russell- H. McCarroll, Dearborn, Mich., assignorsto Ford Motor Company, Dearborn, Mich., a coi'pora tion of Delaware Application May. 23, 1942, Serial No. 444,207

Claims.

This invention relates to production machines -for centrifugal castings; and, more particularly, to a casting machine in which a plurality of different objects may be cast simultaneously by the application of centrifugal forces.

Numerous devices have been developed in the course of years to utilize centrifugal force in the casting of metallic objects. These have generally been vof a type 'best exemplified by those used in casting iiywheels and steel wheels in which the prime consideration was to obtain a dense and homogeneous periphery of the article while the central portion ofthe article was generally removed in finishing to permit its attachment to a shaft or axle. More lately, `centrifugal casting has been extended to an ever-widening field. Many articles, however, which could be improved in some respects, if made by centrifugal casting, have not been so produced because a solid and uniform structure was required throughout and l the available methods of centrifugal casting make it difficult to-obtain this structure.

Theseearlier methods, as best illustrated in the casting of car wheels or pipes, provided for rotation of the mold about the axis of rotation of the article to be cast rand thus otbained the desired peripheral structure. However, this limited the types of articles that could be cast and in many cases it required excessive rotational speed of the mold due to the relatively small diameter of the article. Further, the high speeds required limited the eld to axially symmetrical articles to'avoid l, severe stresses due to unbalanced loads; and but one article could be conveniently cast at one time.

`in the present method, the articles to be cast arel arranged radially about the axisof rotation of the machine and revolve about that axis. They do not, then, have axial voids and are of uniform structure throughout. The rotational speedmay be kept low because the radius, which determines the centrifugal force, is not dependent upon the l dimensions of the object to be cast but merely on i .the location of it on'the casting machine with reference'to the axis of rotation. Nonsyrnmetrical articles may be cast and it is possible to cast a large number of objects at once.

Theapplication of this method `of casting to these problems and structure employed in carry- ,l it outboth possess the attributes of novelty and invention as demonstrated by themany advantages which ilow from its use.

with these and other objects in view. the mvention consists of the arrangement, construction and combination of various parts of the improved device, 'as described in thel specication, claimed m the claims and illustrated in the accompanying drawing in which:-

Figure 1 is a pian view of a casting machine, certain portions being broken away to show the underlying structure.

Figure 2 is an elevation, portions thereof being shown in section as indicated by the line 2--2 on Figure 1.

Numeral Ill ndicates generally a centrifugal casting machine hich includes a pedestal il, in which is Journaled the'spinner shaft I2 supporting the table I3. The shaft and the table are rotated by a beveled gear drive l, the driving'motor used not being shown. Secured to the top of the table I3 is a central ring I5 and adjacent the periphery and circumferentially spaced are a number of cradles i6 and hinge supports Il'. Sup-1 ported between each of the cradles I6 and the radiallyaligned portion'of the central ring i 5 is aY semi-cylindrical lower mold support i8 having flanged edges I9 and pivotally mounted o n each of the hinge supports il is a corresponding semicylindrical upper moldl cover 20 with corresponding flanges 2 I.

The reservoir block 22 is seated in the central ring I3 and is made up of a number of individual is entirely surrounded and protected bythe metallic casing so formed. The mold 29 has an interior cavity 30 which in this case is used to mold a solid artillery shell. The mold 29 is likewise made of a baked refractory material which may be formed vinitially in two parts and joined together by cementing, but which preferably is molded integrally and includes the reinforcing screen 32. When the mold is in place between the mold support and the mold cover, toggle locking means 33 are employed to hold the mold cover in close contact with the support during the casting operation. 'I'hese clamps are shown in their closed position on theleft open on the right side.Y

f In production. the mold coverV 2li at each of the side of Figure 1 and assembled reservoir block 22 is then placed in the central ring and the size of'these elements is so governed that a very close nt is obtained between the block and the abutting molds, these being proportioned slightly oversize so that tight contact is assured, and any excess material is readily reentire group of cast objects may be removed as a star-shaped unit preparatory to cutting o the sprues and cleaning. Similarly, the lower mld supports i8 may be lifted from their cradles for cleaning; and, when replaced, the operation may be repeated.

Some of the'advantages which iiow from this construction are to be found in the provision of the large central basin used which permits a considerable source of molten metal to be accumulated prior to it`s projection to the interior of the mold. Moreover, all of the portions of the apparatus in contact with molten metal may be made of replaceable refractories and hence there is no delay for cleaning or disengaging the cast object from the mold, as is found when reusable molds such as those of rubber or metal are used. The provision of the hinged upper covers 20 present an additional safety factor in that if the covers should open during rotation, they i will be in a position which will still retain the mold and the metal therein from flying out due to centrifugal force. Thev particular arrangement used is well adapted to production work in that a large number of the objects may be made at each casting and the cycle of operation is such that work may be readily removed and new molds placed.

Another advantage is to be found in the ease with which this equipment can be adapted to the casting of diderent articles. Any number ofy molds may be designed to fit the particular mold holders. Thus, by merely interchanging dierent molds, any number of diierent articles may be cast using the same machine, though it is advisable that -in any one cycle,`the same article be cast to keep the table properly balanced. As each of the mold stations is karranged radially and' angularly separated, there is adequate provision for cooling and no diiiiculty is encountered onA this score. It will be noted in Figure 2 that the lower `mold support is spaced a, considerable distance from the table, thus allowing fxiee circulation of air around the entire structure.- This, too, permits the continuous use of the apparatus in quantity production. It will be noted that this apparatus is particularly suited to the production of those objects which must be of uniform metallic constituency throughout. As the objects are spaced radially of the axis of rotation rather than aligned with it, as in the conventional car wheel, cast pipe or cylinder liner machines, there is no tendency to produce a hollow axial portion or pipe. It is preferable that sufficient metal be available to ll the molds, the sprues, and at least partially iill the basin of the reservoir to be drawn upon during cooling to prevent' cooling asvaoaa checks. Of course, .if the metal remaining in the basin is to be drawn into the objects, itis essential that it remain in a semiuid condition and this is permitted because of the large quantity oi' metal present and the facty that it is partially insulated against cooling by the relatively massive refractory walls Voi? the reservoir. Sincethe article, as shown, has a relatively large section adjacent the gate, the metal in the gate, being between the article and the reservoir, is kept in a fluid condition by the heat from these two sources and continued iiow of metal therethrough to the article is permitted as long as the latter requires it during the cooling stages.

Some changes may be made in the arrangement, construction and combination of the various parts of the improved device without departing from the spirit of the invention. It is the intention to cover by the claims such changes as may be reasonably included within the scope thereof.

` The invention claimed is:

1. In a centrifugal casting machine, a horizontal table rotatably mounted, means to rotate said table, a reservoir 4support in the center of said table, a removable reservoir of refractory matcrial received in said reservoir support, individual mold stations arranged radially of said table, including a cradle and a cover support, mold supports extending between said reservoir and said outer cradle, individual molds received in said mold` support and in communication with said central reservoir, said molds being of refractory materiahindividual covers at each station hinged to said support and adapted to enclose said mold, and means to lock said covers in their s closed positions.

2. In a centrifugal casting machine, a horizontal table rotatably mounted, means to rotate said table, means disposed centrally of said table to receive a replaceable reservoir of refractory material, said reservoir including a basin of subof refractory material received in said supports and in communication with said gates, means hinged adjacent the outer edge of said table at i said mold stations and adapted to enclose said molds, and means to lock said mold covers in their closed positions. v

3. In a centrifugal casting machine, a horizontal table/rotatably mounted, means to otali'fe said table, retaining means centrally disposed on said table, a'replaceable reservoir block of refractory material received in said retaining means, said reservoir having a basin of substantial capacity and gates leading therefrom at spaced intervals therethrough, a plurality of molding stations radially arranged on said table corresponding to said gates, said molding stations being symmetrically arranged, a cradleA and a, hinge post at each said station, a lower mold casing supported thereby at each said station, a mold cover hingedly supported at said hinge post and adapted to forman enclosure with said lower mold casing, and means to lock said cover and said casing to form receptacles abutting said central reservoir.

4. In a centrifugal molding machine, in combination, a horizontal table rotatably mounted, means to rotate said table, a replaceable refracstations. a mold casing comprising a lower mold support and a cover hingedly secured adjacent the outer periphery of said table at -each said station, said mold support and coverdening a substantially cylindrical mold enclosure, molds of substantially cylindrical outer configuration received at each said mold station', a mold cavity lllliilliil.V Said mold-'dening the Object t0 be cast,

a basin of substantial size in said reservoir block,

gates through said reservoir blocks aligned with each said mold station and communicating withsaid mold, cavities, the outer surface of said reservoir block at each said mold station co-operblock in saidretaining means, mold stations ar.- ranged radially and symmetrically on said table,

each said mold station including a cradle and a hinged post, a lower mold casing received in each said cradle, an upper mold casing hingedly attached to said mold post, said casing parts, when closedLdening a substantially cylindrical mold enclosure, a mold of substantially cylindrical outer conformationl received in said mold casing and abutting said reservoir block, a basin of substantial capacity in said reservoir block, gates in said block communicating with said basin and said mold cavities, the outer wall oi' said reservoir block at each said station serving as one face of the mold cavity, said mold support being spaced from the upper surface of said table, and readily Vreleasalole means to lock said upper casing in its closed position.

' CEAS. E. SORENSEN.

RUBSEIL H. MCCARROLL.

said table, a replaceable refractory reservoirV e 

